Panasonic PV-V4525S, Service Manual

Page: 15 / 46

6.1. MECHANICAL ADJUSTMENT
Refer to the Service Manual for R4-Mechanism Chassis for PV-
Model (Order No. MKE0401000C1).
6.2. ELECTRICAL ADJUSTMENT
6.2.1. TEST EQUIPMENT
To do all of these electrical adjustments, the following
equipment is required.
1. Dual-Trace Oscilloscope
Voltage Range: 0.001 V to 50 V/Div.
Frequency Range: DC to 50 MHz
Probes: 10:1, 1:1
2. Isolation Transformer (Variable)
3. VHS Alignment Tape (VFMS0003H6)
4. TV monitor
6.2.2. HOW TO READ THE ADJUSTMENT
PROCEDURES
Fig. E1
6.2.3. EVR (Electronic Variable Register)
ADJUSTMENT WITH THE REMOTE
CONTROL
This unit has electronic technology using I
2
C Bus concept.
The PG SHIFTER ADJUSTMENT is adjusted by using "On
Screen Displays" and the remote control instead of adjusting
mechanical controls (VR).
6.2.4. PG SHIFTER ADJUSTMENT
Purpose: Determine the Video Head Switching Point during
Playback.
Symptom of
Misadjustment: May cause Head Switching Noise and/or Vertical
Jitter.
Test Point : TP3001 (Main C.B.A.),
TP6205 (Main C.B.A.)
Specification: T = 6 H ± 0.5 H (0.38 ms ± 0.03 ms)
Mode : SP Playback
Equipment : Oscilloscope,
VHS Alignment Tape (VFMS0003H6),
TV monitor
1. Insert the VHS Alignment Tape. Enter service mode by
pressing and holding FF and CH UP buttons on VCR
together for more than 5 seconds.
2. Play back SP mode. Then, press 100 button on the remote
to enter EVR PG SHIFTER ADJUSTMENT mode. PG
ADJUSTMENT screen will appear on the TV Monitor.
Fig. E2
3. Connect the channel-1 scope probe to TP3001 and the
channel-2 scope probe to TP6205. Used TP6205 as a
trigger
4. Adjust value so that the trailing edge of the head switching
pulse is placed 6 H ± 0.5 H (0.38 ms ± 0.03 ms) before the
start of the vertical sync pulse by pressing CH UP and CH
DOWN buttons on the remote.
Fig. E3
6 ADJUSTMENT PROCEDURES
15
PV-V4525S / PV-V4535S-K / PV-455S-K